1. Keyboard
A keyboard is the today's most common and familiar input device.
A keyboard primary function is to act an input device.
2. Mouse
A mouse is a pointing device and it has been around more than 20 years.
The mouse usually contains one to three buttons. As the user rolls on a flat surface, the mouse control the cursor on the screen.
Advantages
- It is simple device and very easy to use.
- It is not that very expensive.
- It moves the cursor faster than the arrow keys of keyboard do.
Disadvantages
- The movement of the cursor is not very sensitive to movement of mouse.
- If the contact between wheels and mouse pad is lost, the cursor does not move.
Joysticks
A joystick is also a pointing device.
It is used to move the cursor position on a CRT screen.
Its function is similar to a mouse, except that with a mouse the cursor stops moving as soon as you stop moving the mouse.
A joystick is a stick which has spherical ball at its lower end as well as at its upper end.
A joystick uses a lever to control the position of the cursor.
It internally translates the lever position and speed with which the joystick is moved into digital signals that are sent to the computer to control the cursor movement.
Most joysticks include two buttons called triggers.
Trackballs
Trackball is another pointing device.
A trackball is a mouse lying on its back.
A trackball uses a hard sphere to control cursor movement.
The ball can be rotated by hand in any direction.
The associated electronic circuitry detects the direction and speed of spin.
Comments